A security source said the executions were carried out at Swaqa prison, south of the capital Amman.

Jordan had promised to begin executing death-row Islamic extremists at daybreak in response to the murder of Muaz al-Kasasbeh, who was captured by IS when his plane went down in December.

Rishawi, 44, was condemned to death for her participation in deadly attacks in Amman in 2005 and IS had offered to spare Kasasbeh's life and free a Japanese hostage - who was later beheaded - if she were released.

Jordan had on Tuesday vowed an "earth-shattering" response to the killing of Kasasbeh, hours after a harrowing video emerged online purporting to show the captive and caged 26-year-old F-16 fighter pilot engulfed in flames.

The video released on Tuesday by the Islamic State (IS) group appears to show the captured Jordanian pilot Muaz al-Kasasbeh being burnt alive in a cage.

Though the video is unverified, its release comes a week after a previous deadline set by IS for a hostage exchange with an al-Qaeda suicide bomber imprisoned in Jordan, Sajida al-Rishawi.

However, a variety of sources, including Jordanian TV and activists from the group Raqqa is Being Silently Slaughtered (RIBSS) – an anti-IS organisation based in the IS ‘capital’ of Raqqa – have claimed that Kasasbeh had been killed in early January.

Were it true that Kasasbeh was killed in January, it would make a farce of the hostage negotiations between the Jordanian government and IS, as well as question the sincerity of IS’s desire to see Rishawi released.

Shortly after the release of the video the Jordanian information minister told Sky News Arabia that IS had been “playing games” during their negotiations.

The video ends with a promise of “100 gold dinars” to “whoever kills a crusader pilot” referring to those fighting IS in the US-led coalition.

“Good tidings to whoever supports his religion and achieves a kill that will liberate him from hellfire,” reads the slide, translated both in Arabic and English.

They then show a “database” with photos, names, addresses and occupations of Jordanian pilots fighting with the coalition, with the words “wanted dead” written above their photos.

The Jordanian government had previously threatened to execute scores of IS and al-Qaeda prisoners were Kasasbeh to be killed.

It was previously thought that Kerbouli, an Iraqi national, was previously demanded by IS in exchange for Kasasbeh as well as Rishawi.

Mohammed al-Shelabi Abu Siyaf, a leader of Jordan’s Salafist Jihad Current, told Sham Times last December that Kerbouli was a member of IS and a high-level aide to Abu Mus’ab al-Zirqawi. He was wanted in Jordan over the killing of a Jordanian driver, Khalid al-Dessuqi, who was killed just over the border in Iraq in September 2013.

“They will do it to pacify the Jordanian people in general, as well as Kasasbeh’s family,” Adnan Abu Owda said.

International condemnation

King Abdullah II, who was visiting Washington as the video came to light, recorded a televised address to his shocked and outraged nation.

The king, who was once in the military himself, described Kasasbeh as a hero and vowed to take the battle to Islamic State extremists, who have executed several captives on camera in recent months, provoking worldwide revulsion.

The Jordanian army released statement saying the blood of Kasasbeh would "not be spilt in vain."

"Our punishment and revenge will be as huge as the loss of the Jordanians," it read.

Though his meeting with Abdullah was abruptly cut short, US Vice President Joe Biden said he condemned, in the strongest possible terms, "the brutality and violence that ISIL has consistently shown to its captives and to the people of Iraq and Syria," according to a press release from the White House.

US President Barack Obama, who hosted Abdullah in a hastily organised and brief Oval Office meeting, led widespread international condemnation of the latest graphic murder, decrying the "cowardice and depravity" of the Islamic State group.

"The president and King Abdullah reaffirmed that the vile murder of this brave Jordanian will only serve to steel the international community’s resolve to destroy ISIL," a National Security Council spokesman said after the pair met.

The Obama administration had earlier reaffirmed its intention to give Jordan $3 billion in security aid over the next three years.

Iraqi PM Haider al-Abadi condemned the killings, and is also reportedly "mulling" the idea of executing his own IS and al-Qaeda prisoners, according to Conflict News.

Hundreds gathered outside a cultural association in al-Karak on Tuesday, the province where Kasasbeh was born.

There were reports of gunshots being fired, and the correspondent of Lebanese news site al-Mayadeen reported a “riot” taking place.

Sky News reported that a government building had been set alight.

The hashtag #WeAreAllMuaz is the number 1 trend in Jordan.

The killing is likely to provide further ammunition for a vocal movement in Jordan opposed to the country's involvement in the anti-IS bombing campaign.